Air heater



Aug. 28, 1934.

M. I. LARSEN 1,971,531

AIR HEATER Filed March 2, 1933 2 Sheets-Sheet l 1934. M. 1. LARSEN 1,971,531

AIR HEATER Filed March 2, 1933 2 Sheets-Sheet 2 Patented Aug. 28, 1934 UNITED STATES PATENT OFFICE 1,971,531 Am HEATER Martin I. Larsen, Chicago, Ill. Application March 2, 1933, Serial No. 659,379

11 Claims. (01. 125-90) This invention relates to improvements in stoves and pertains particularly to an improved air heater.

The primary object of the present invention is provide a new and novel heating stove which is so designed that the maximum heating eiiect will beobtained from the fuel used.

Another object of the invention is to provide an improved heating stove wherein the products of-combustion are circulated through passageways encased in an air jacket; so that amaximum of the heat generated by the fuel may be taken up by the air in the casing for discharge into the atmosphere outside the heater.

A still further object of the invention is to provide a new and novel arrangement of heating units by which maximum efficiency is obtained and which will at the same time form a neat and attractive structure.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of thedrawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims. r

' In the drawings:--- r i Figure 1 is a vertical section through the heater embodying the present invention;

Figure 2 is a sectional View taken upon the line 2--- of Figure '1; I

Figure 3 is a sectional view taken substantially upon the line 3--3 of Figure 1.

Referring now more particularlyto the drawings "wherein like numerals of reference indicate corresponding parts throughout the several views, the numeral 1 indicates the base forthe present heater over which is vertically supported by the feet 2 the tubular standard 3, the feet 2 resting upon and being secured to the base 1. Upon theupper end of the tubular standard 3 there is secured the collar 4 with which is in tegrally formed the lateral flange 5 and this flange supports the plate 6 whichis preferably inthe form of a disk and which hasa central aperture through which the upper endotthe standard 3 passes.

Mounted upon the plate 6 isa circular structure indicated generally by the numeral 7 and consisting of a vertical wall 8 and the annular inwardly extending wall 9 which is preferably integral therewith. The free inner edge of the annular inwardly extending or top wall 9 is turned upwardly to form theiiange l0 and the lower edge of the vertical wall 8 has asurround ing portion turned outwardly to form'the base flange .11 which rests upon the plate 6 and is secured thereto by the bolts or rivets 12 or in any other suitable manner.

Disposed within the circular structure '7 is the lower'end of a frusto conical body which is indicated generally by the numeral 13 and which is transversely divided to form the upper and lower sections 14 and 15 respectively. These sections 14 and 15 have formed at their abutting edges the flanges 16 and 17 which are bolted or otherwise suitably secured together. The lower edge of the portion 15 engages and is secured to the inner face of the wall 8 of the circular unit 7 in the manner shown and the'flange which is formed integral with the horizontal top wall 9 of the unit. 7 abuts and is secured to the portion of the frusto-conical body 13. There is thus formed by the portion 15 of the body 13 andby the walls 8 and 9 the annular heat chamber 18 into which the interior of the unit 13 opens through apertures 19. As illustrated the upper section 14 of the frustoconical body is formed of material of a thicker or heavier gage than the lower portion 15. The lower portion is preferably formed of galvanized iron while the upper portion 14 is preferably formed of brass. 7

Cast integral with the upper end of the portion 14 is a vertical cylindrical unit which opens downwardly into the irusto-conical body and which is indicated generally by the numeral 20. This unit 20 together with the frusto-conical body 13 con: stitutes the combustion chamber of the heater.

The side wall of the unit 20 is provided with a plurality of vertical passages or fiues 21 each of which opens downwardly through the inner wall of the portion 14 while at its upper end each opens into a transverse pasage 22 formed through the wall of the unit. Into the outer end of each of these transverse passages 22 is fitted one end of a tube which is indicated as a whole by the numeral 23. Each of these tubes has a horizontal upper portion 24 which is arcuate as shown in Figure 2 and which extends radially from the head 20. This upper portion 24 merges into a vertical por tion'25 and this in turn connects with or merges into a lower horizontal portion 26 which extends in toward and passes through the wall 3 to open into the annular heat chamber 18.

By the provision of the vertical passages 21 in the unit 20 the very thick wall of this unit is made to take up more heat than it would otherwise do except after the heater has been in operation for a considerable period, thus making use of the maximum amount of heat developed almost immediately the burner is lighted.

Disposed within the circular area defined by the vertical portions of the heat conducting pipes 23 are two helical tube coils which are indicated by the numerals 2'7 and 28. These tube coils are of larger cross sectional diameter than the tubes 23 and as shown in Figure 1. one coil is of an overall diameter greater than the other so that they are in nested relation and have the combustion chamber disposed centrally thereof.

The lower ends of the heat coils or tubes 27 and 28 pass through the wall 3 of the annular chamber 18 at diametrically opposite points as indicated by the numerals 29 and 30 respectively and as shown each is directed toward one of the openings 19 in the lower portion 15 of the frusto-conical body. ihe upper ends of these coils lead away from the heater in parallel relation as indicated at 31 and 32 to be connected with a chimney or some other suitable means of conducting away the products of combustion.

By the provision of openings 19 some of the hot gases constituting the products of combustion and heated air which pass through the pipes 24 into the annular chamber 18 will reenter the combustion chamber and be recirculated so that the maximum amount of heat carried thereby will be taken up by the surrounding air.

Enclosing the coils 27 and 28, the combustion chamber and the tubes 23, is a shell which is indicated generally by the numeral 33. This shell is preferably of circular design as illustrated, although it is to be understood that the invention is not to be confined to this particular design. The shell 33 consists of a head 34 which overlies the coils and rests upon the head portion 20 of the combustion chamber, the circular side or vertical wall 35 and the bottom wall 36 which extends inwardly toward and terminates in spaced relation with the wall 8 or" the annular structure 7, thus forming, as indicated by the numeral 37, an opening or passage through which air may enter the shell or casing 33 to be heated by the pipes and tubes therein.

For the discharge of the heated air from the shell 33 the side wall 35 thereof is provided with a plurality of slots 38 each of which is covered by a downwardly and outwardly directed deflector 39. A suitable sleeve is formed in the wall 35 as indicated at 40 for the extension from the casing of the lead-off pipes 31 and 32 of the coils.

Mounted in any suitable manner within the lower part of the structure 7 and facing upwardly into the frusto-conical unit 13 is a burner unit 41. This unit is illustrated as being of the type employed for burning gas and has leading thereto the gas pipe 42. It is, of course, to be understood that any other type of unit may be employed for heating the air within the shell 33, such, for ex ample, as an electric unit.

The wall 8 of the annular unit at the lower part of the combustion chamber is provided with an opening 43 to facilitate the introduction of a match or other suitable means for igniting the fuel issuing from the burner 41.

As will be readily apparent, the standard 3 being supported at its lower end above the floor or other surface upon which the stove is resting, provides a means by which air is supplied to the burner unit. The flow of air through this passage is controlled by a fiat sliding member 43, the outer end of which is provided with a means 44 by which it may be grasped to facilitate its being shifted in the desired direction.

From the foregoing it will be readily apparent that the stove embodying the present invention may be economically constructed and will present an attractive appearance so that it may be used in living rooms or other similar locations and due to the manner in which the products of combustion from the fuel burner are collected in the top of the frusto-conical combustion unit and then conducted through the series of passages and coil within the shell into which the air is passed to be heated, the maximum of heating effect will be obtained. At the same time the stove is so constructed that there will be no danger of poisonous fumes escaping into the room.

Having thus described the invention, what is claimed is:-

1. An air heater, comprising a combustion chamber, a fuel burner within the chamber, an annular chamber surrounding the combustion chamber, a pipe disposed in the form of a coil around the combustion chamber and having one end opening into said annular chamber, a pipe leading from the upper part of the combustion chamber into said annular chamber to conduct the products of combustion and other heated gases to said first pipe, the other end of said first pipe constituting a discharge for the heated gases, and means for maintaining a circulation of some of the heated gases and products of combustion through a circuit including the combustion chamber, said annular chamber and the second mentioned pipe.

2. An air heater, comprising a hollow frustoconical body, a hollow head upon said body and opening thereinto, a heat generating element in the lower part of said body, said body and head constituting a combustion chamber, passages extending laterally through the walls of said head, a pipe in the form of a vertical coil surrounding the combustion chamber, and a plurality of pipes extending from said passages and leading to and connecting with the lower end of said coil, the other end of said coil providing a lead-off means for the products of combustion passing therethrough.

3. An air heater, comprising a hollow frustoconical body, a hollow head upon said body and opening thereinto, a heat generating element in the lower part of said body, said body and head constituting a combustion chamber, passages extending laterally through the walls of said head, a pipe in the form of a vertical coil surrounding the combustion chamber, and a plurality of pipes extending from said passages and leading to and connecting with the lower end of said coil, the other end of said coil providing a the lower part of said body, said body and head constituting a combustion chamber, passages extending laterally through the walls of said head, a pipe in the form of a coil surrounding the combustion chamber, and a plurality of pipes extending from said passages and leading to and connecting with one end of said coil, the other end of said coil providing a lead-01f means for the products of combustion passing therethrough, said hollow head having a vertically fol disposed side wall and having vertical passages formed in said side wall, and opening at their lower ends into the combustion chamber and each opening atits upper end into a lateral passage for communication with the pipe leading therefrom.

LoS'

5. A heater, comprising a vertically disposed hollow frusto-conical body, a hollow head upon the upper end of said body and opening thereinto, said body and head constituting a combustion chamber, said head having a vertical wall provided with a plurality of vertical passages each opening at its lower end into the combustion chamber, the said head further having a plurality of passages passing laterally through the vertical wall and each having a vertical passage opening thereinto, a casing formed about the lower part of said combustion chamber, a pipe leading horizontally outwardly from each of said lateral passages and then leading downwardly and inwardly to and into said casing, a second pipe in the form of a coil surrounding said combustion chamber and having one end leading from said casing, the other end of the second pipe constituting a lead-off for products of combustion generated in the combustion chamber, and a fuel burner within the combustion chamber, said combustion chamber having an aperture inthe wall thereof leading into the surrounding casing.

6. A heater, comprising a vertically disposed hollow frusto-conical body, a hollow head upon the upper end of said body and opening thereinto, said body and head constituting a combustion chamber, said head having a vertical wall provided with a plurality of vertical passages each opening at'its lower end into the combustion chamber, the said head further having a plurality of passages passing laterally through the vertical wall and each having a vertical passage opening thereinto, a casing formed about the lower part of said combustion chamber, a pipe leading horizontally outwardly from each of said lateral passages and then leading downwardly and inwardly to and into said casing, a second pipe in the form of a coil surrounding said combustion chamber and having one end leading from said casing, the other end of the second pipe constituting a lead-off for products of combustion generated in the combustion chamber, a fuel burner within the combustion chamber, said combustion chamber having an aperture in the wall thereof leading into the surrounding casing, and a second casing enclosing said pipes and having an air inlet opening in its lower part and air outlet openings whereby a circulation of air may be maintained therethrough for contact with said pipes.

'7. A heater, comprising a vertically disposed hollow frusto-conical body, a hollow head upon the upper end of said body and opening thereinto, said body and head constituting a combustion chamber, said head having a vertical wall provided with a plurality of vertical passages each opening at its lower end into the combustion chamber, the said head further having a plurality of passages passing laterally through the vertical wall and each having a vertical passage opening thereinto, a casing formed about the lower part of said combustion chamber, a pipe leading horizontally outwardly from each of said lateral passages and then leading downwardly and inwardly to and into said casing, a second pipe in the form of a coil surrounding said combustion chamber and having one end leading from said casing, the other end of the second pipe constituting a lead-01f for products of com bustion generated in the combustion chamber,

a fuel burner within the combustion chamber, said combustion chamber having an aperture in the wall thereof leading into the surrounding casing, said combustion chamber being closed at its bottom, a vertical tubular standard extending at its upper end through the bottom of the combustion chamber, and supporting means at the lower end of said standard whereby it is maintained in vertical position with its lower end raised from the underlying supporting surface.

8. In an air heater, an elongated vertically disposed casing constituting a combustion chamber, a heating element in the lower part thereof, a chamber surrounding the lower part of the easing, pipes leading from the top of said casing to said last chamber, and a vertical pipe coil extending the length of and surrounding the casing and connected at its lower end with said last chamber, the upper end of said coil constituting an outlet for the products of combustion.

9. In an air heater, an elongated vertically disposed casing constituting a combustion chamber, a heat element in the lower part thereof, a chamber surrounding the lower part of the casing, pipes leading from the top of said casing to said last chamber, and a vertical pipe coil extending the length of and surrounding the casing and connected at its lower end with said last chamber, the upper end of said coil constituting an outlet for the products of combustion, said casing having openings in the wall thereof leading directly into the surrounding chamber.

10. An air heater, comprising an upright conical housing, a fuel burner disposed in the base portion of said housing, means forming a chamber about the inclined wall of the housing, said housing wall forming a wall of the chamber, a pipe in the form of an upright coil having said conical housing disposed centrally therein and having one end opening into said annular chamber, and a pipe leading from the upper part of said housingto and into said annular chamber, for transferring the products of combustion from the upper part of the housing to the annular chamber, the said coil pipe constituting a heating element and a means for carrying off the products of combustion.

11. An air heater, comprising an upright conical housing, a fuel burner disposed in the base portion of said housing, means forming a chamber about the inclined wall of the housing, said housing wall forming a wall of the chamber, a pipe in the form of an upright coil having said conical housing disposed centrally therein and having one end opening into said annular chamber, a pipe leading from the upper part of said housing to and into said annular chamber, for transferring the products of combustion from the upper part of the housing to the annular chamber, the said coil pipe constituting a heating element and a means for carrying off the products of combustion, a wall closing the lower part of said housing beneath the fuel burner, a vertical tubular standard having its upper end passing through said wall and having its lower end open, and supporting legs secured to and maintaining said standard in upright position and in spaced relation with the surface upon which they rest, said standard constituting an air supply passage to the fuel burner.

MARTIN I. LARSEN. 

